depending on contents of baggage you can also try FedEx or UPS to ship your luggage. there are also luggage services. while this isn't cheap, it will be less than 8k. also, staying a night at ICN isn't bad. we did a couple of days on our way to Beijing a couple years ago. saw some interesting sites, learned more history and have great stories from school kids wanting to practice their English. it was a fun stopover.